1. Field of the Invention
The present invention relates to the field of data storage. More particularly, the present invention relates to a device for recording and detecting data marks within a multi-layered storage media.
2. Description of the Related Art
Digital optical data storage devices, such as multi-layered optical disks, store information in the volume of a recording media, as well as at the surface of the media. Volume optical storage techniques have been demonstrated using multi-layered media by focusing a laser beam on individual layers within the media. Further, the ability to image objects buried within semi-transparent, turbid, or highly scattering material with a high-depth resolution is important for many optical tomography applications. For example, see H. Coufal, "Optical Tomography?," J. Mol. Structure, Vol. 347, 285 (1995). Previously, the ability to image buried objects could only be accomplished using a variety of time-gated optical imaging techniques requiring expensive picosecond or femtosecond lasers and fast optical detection techniques. For example, see L. Wang, P. O. Ho, X. Liang, H. Dai, and R. R. Alfano, "Kerr-Fourier Imaging of Hidden Objects in Thick Turbid Media," Optics Letters, Vol. 18, No. 3, Feb. 1, 1993, pp. 241-243. Interferometric methods have also been developed, such as laser-feedback interferometry, which detect perturbations caused by light scattered from a buried object reentering the laser cavity. For example, see Robert Cassidy, "Laser Feedback Microscope Offers Resolution Rivaling SEM," Research and Development, Vol. 37, No. 6, May 1995, pp. 83-84; T. L. Wong, S. L. Sabato, and A. Bearden, "PHOEBE a Prototype Scanning Laser-Feedback Microscope for Imaging Biological Cells in Aqueous Media," J. of Microscopy, Vol. 177, Pt. 2, February 1995, pp. 162-170; and A. Bearden, M. P. O'Neill, L. C. Osborne, and T. L. Wong, "Imaging and Vibrational Analysis with Laser-Feedback Interferometry," Optics Letters, Vol. 18, No. 3, Feb. 1, 1993, pp. 238-240. These conventional interferometric approaches, however, require a controlled feedback positioning system for mapping the buried interface and are similar to other scanning confocal microscopes.
What is needed is an inexpensive way for recording digital data onto a multi-layered optical disk and then for reading the recorded digital data.